The invention relates to printed circuit card installation in electronic devices. More particularly, the invention relates to a structure and method for auto docking electronic cards engaged by a carrier to be xe2x80x9chot pluggedxe2x80x9d into an electronic device.
Electronic equipment technicians, and indeed some private individuals as well, are aware that printed circuit boards (PCB) are employed within many pieces of electronic equipment. It is also known by these individuals that these xe2x80x9ccardsxe2x80x9d can in some cases be removed for repair of a device or an upgrade thereof or simply to alter the operating parameters thereof. Most notable are computer devices where different functions or memory capacity can be needed.
Conventionally, the changing of a card is done by removing the cover of the machine and manually removing the existing card and plugging in a new one. This procedure may be complicated further in systems where entire banks of cards must be removed above the one being replaced or the bank of cards where one is to be replaced must removed. In such instances the machine must be shut down. Since both the shut down and start up procedure can be time consuming, shut down is undesirable.
More recently, some electronic equipment has been designed to accept a card carrier comprising a frame with means to insert the card into an electrical receptacle while the cover is still in place on the device. This type of an operation is known as xe2x80x9chot pluggingxe2x80x9d. While the existing hot plugging PCI card carriers are effective and beneficial for their intended purpose, they are card specific. Unfortunately, then, one needs a specific carrier for every type of card he wishes to use.
Examples of such carriers are described in detail in U.S. Pat. No. 6,071,143, filed Dec. 13, 1996, U.S. Pat. No. 5,868,585, filed Dec. 13, 1996, and U.S. Pat. No. 5,815,377, filed Dec. 8, 1997, all assigned to the assignee hereof and all of which are fully incorporated herein by reference.
In mid sized or mini computers it is common to have continuous operation of the computer system. Thus, the installation or replacement of peripheral devices must be effected by hot plugging without disturbing system operation. However, PCI cards, in the normal environment, are installed when the device is shut down and the covers removed for card installation and removal. To realize the benefits of PCI card use, it is necessary to find a means to accomplish hot plugging of such cards while protecting the user from the electrical hazards of an operating, electrically energized system, while minimizing the space needed to employ such a capability. Moreover, mainly for reasons associated with long-term system operation and reliability, it is likewise very desirable to be able to easily insert and remove these printed circuit cards even when they are disposed in very tight spaces. The insertion and removal operations are also provided as an important part of a xe2x80x9chot-pluggabilityxe2x80x9d function which is very desirable for xe2x80x9con the flyxe2x80x9d repairs, replacements, maintenance and upgrades.
With increased circuit density there has also been a concomitantly driven increase in the number of power, signal and control lines which require electrical connections to be made between printed circuit cards and printed circuit boards. This means that the electrical connectors that carry these various electrical circuits between the cards and the boards have been required to carry more and more separate individual connections. A significant consequence of the increase in the number of individual electrical connections, all of which require surety of contact, is the corresponding increase in the force needed to insert printed circuit connectors into mating printed circuit board sockets. This aspect provides special design considerations for card holders that carry printed circuit cards which are meant to be inserted into printed circuit boards via actuating mechanisms.
It is also noted that the present discussion refers to printed circuit boards and printed circuit cards. As contemplated herein, the printed circuit board is the larger component into which at least one printed circuit card is inserted for purposes of electrical connection. The present disclosure places no specific limits on either the size of a printed circuit board or the size of a printed circuit card. In the most general situation, a circuit board will be populated with a plurality of printed circuit cards. That is, the printed board will have a number of printed circuit cards inserted therein. Accordingly, as used herein, the terms xe2x80x9cprinted circuit boardxe2x80x9d and xe2x80x9cprinted circuit cardxe2x80x9d are considered to be relative terms.
Accordingly, the present inventors are presented with the following sometimes competing packaging problems: connector pin alignment, card holder alignment, rigid connection to a printed circuit board, dense and close packaging, hot pluggability, the desire to provide an easy-to-load card holder for carrying printed circuit cards, and mechanisms requiring a mechanical advantage for insertion and removal of printed circuit cards.
The problems associated with hot plugging of PCI cards is resolved using a card holder that slides into the enclosure prior to electrical connection. The card is aligned with the connector when fully inserted and is thereafter cammed into the cooperating connector. The camming assembly is mounted on a surface above and proximate the mother board where it provides mechanical advantage during insertion and removal of the PCI card.
The card holder includes a translatable location of support slidably connected to the card holder for mounting edges of the circuit card thereon. A guide assembly is mounted within the enclosure on the surface above and proximate the mother board for slidably supporting and guiding the card holder into the enclosure to a position whereat a circuit card connector of the card is aligned with a card socket extending from the mother board. The camming assembly includes a cam mechanism providing mechanical advantage when a cam mechanism is operated outside of the enclosure to move said card holder toward the mother board and insert the circuit card connector into the socket. The cam lever extends outside the enclosure to convert horizontal or pivoting motion of the cam lever to vertical motion of the card into and out of the socket.